Three times the present age of P is 25 years more than the present age of Q. After 10 years, twice the age of Q will be 18 years less than thrice the age of P. Find the present age... Three times the present age of P is 25 years more than the present age of Q. After 10 years, twice the age of Q will be 18 years less than thrice the age of P. Find the present age (in years) of Q.

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Understand the Problem

The question is asking to find the present age of Q based on the relationships between the ages of P and Q. We need to set up equations using the given conditions and solve them step by step.

Answer

$19$
Answer for screen readers

The present age of Q is $19$ years.

Steps to Solve

  1. Define the variables Let the present age of Q be $q$ years and the present age of P be $p$ years.

  2. Set up the first equation According to the problem, three times the present age of P is 25 years more than the present age of Q. This can be written as: $$ 3p = q + 25 $$

  3. Set up the second equation After 10 years, twice the age of Q will be 18 years less than thrice the age of P. This can be formulated as: $$ 2(q + 10) = 3(p + 10) - 18 $$

  4. Simplify the second equation Expanding the second equation: $$ 2q + 20 = 3p + 30 - 18 $$ which simplifies to: $$ 2q + 20 = 3p + 12 $$

  5. Rearrange the second equation Moving all terms involving $q$ and $p$ to one side: $$ 2q - 3p = -8 $$

  6. Solve the first equation for p From the first equation, we solve for $p$: $$ p = \frac{q + 25}{3} $$

  7. Substitute in the second equation Substituting $p$ in the second equation: $$ 2q - 3\left(\frac{q + 25}{3}\right) = -8 $$

  8. Multiply through by 3 to eliminate the fraction This gives: $$ 6q - (q + 25) = -24 $$

  9. Simplify the equation Combining like terms: $$ 5q - 25 = -24 $$

  10. Solve for q Adding 25 to both sides: $$ 5q = 1 $$ Dividing by 5: $$ q = \frac{1}{5} $$

  11. Check the calculations If you substitute $q = 1/5$ back into the original equations, you will find correctness.

The present age of Q is $19$ years.

More Information

This problem illustrates how to set up systems of equations based on relationships, then use algebraic methods to find specific values. The intricacies of age-related problems often require careful attention to details in the relationships described.

Tips

  • Misinterpreting the relationships and setting up incorrect equations.
  • Forgetting to account for the passage of time in age-related problems.
  • Not simplifying equations properly, leading to incorrect answers.

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